A generic drainage apparatus with a housing and a solenoid valve is known from DE 202 17 601 U1. In this case, a second solenoid valve is arranged downstream of the first solenoid valve, wherein both solenoid valves can block an associated outlet opening by means of a movable valve body in each case. The solenoid valves, which are connected downstream of one another, should in particular make it possible to drain separated liquid against a differential pressure.
A filter apparatus with a drainage apparatus is known from WO 2011/022659 A2.
In modern fuel modules, for frictionless operation, the separated water is initially collected in a water collection chamber of the fuel module or fuel filter, and for the most part drained into the environment via an additional adsorption filter, for example an activated carbon filter. As the drainage of the separated water constitutes a highly relevant procedure for the environment, currently two solenoid valves are always connected in series, in order to be able to ensure that if one solenoid valve fails, no fuel is inadvertently drained into the environment.
However, in the case of known drainage apparatuses or filter apparatuses with two solenoid valves connected downstream of one another, the comparatively complicated and therefore also expensive design thereof is disadvantageous.